Add Skiff resources (#1106)

Author: ollybeck

README.md

@@ -181,6 +181,7 @@ Any comments, suggestions? [Let us know!](https://github.com/jaywcjlove/awesome-
 * [QOwnNotes](http://www.qownnotes.org/) - Open-source notepad with markdown support and todo list manager. [![Open-Source Software][OSS Icon]](https://github.com/pbek/QOwnNotes) ![Freeware][Freeware Icon]
 * [Quiver](http://happenapps.com/#quiver) - The Programmer's Notebook, lets you easily mix text, code, Markdown and LaTeX within one note, edit code with an awesome code editor and live preview Markdown and LaTeX.
 * [AliYuQue](https://www.yuque.com/install/desktop) - Cloud note-taking knowledge management, collaboration platform, Markdown based writing, support embedded flow chart, brain diagram, timing sequence, code rendering, Sketch board creation, personal knowledge sharing, etc. Compared to youdao cloud note and evernote similar products, which include all of its functions, support knowledge sharing and more powerful creation, collaboration and editor, it comes from alibaba ant financial.![Freeware][Freeware Icon]
+* [Skiff](https://skiff.com/) - End-to-end encrypted & decentralized email, real-time document collaboration, and file storage designed with zero-trust privacy -- available on web, iOS/Android, and macOS. ![Freeware][Freeware Icon][![Open-Source Software][OSS Icon]](https://github.com/skiff-org)
 
 #### Journaling
 
@@ -645,6 +646,7 @@ Any comments, suggestions? [Let us know!](https://github.com/jaywcjlove/awesome-
 * [ThunderBird](https://www.mozilla.org/en-US/thunderbird/) - Software that makes email easier. ![Freeware][Freeware Icon]
 * [Tutanota](https://tutanota.com/) - Encrypted email focused on security and privacy. [![Open-Source Software][OSS Icon]](https://github.com/tutao/tutanota) ![Freeware][Freeware Icon]
 * [Edison Mail](https://mail.edison.tech/mac) - A customisable, simple, and beautiful email client. ![Freeware][Freeware Icon]
+* [Skiff Mail](https://skiff.com/mail) - Encrypted & Decentralized Email -- available on web, iOS/Android, and macOS. ![Freeware][Freeware Icon] [![Open-Source Software][OSS Icon]](https://github.com/skiff-org/skiff-mail)
 
 #### File Sharing